Lamp socket



Patented Sept. 10, 1940 LAM]? SOCKET Samuel B. Kraut, LakewoodfOhio, assi or to Westinghouse Electric & Manufacturinz company, East Pittsburgh, Pa., a corporationv of Pennsylvania Application October 2'1, 1937, Serial No. 171,362

6Claims.

lem of providing a satisfactory socket for support-- ing and conducting current to such lamps. The

bi-post lamp differs greatly from the well known incandescent lamp having a screw base in that the bi-post lamp has no screw base, but instead, terminals in the form of prongs extend through and are molded into the base of the glass envelope of the lamp. These prongs are used not only to conduct current to the filament but also to support the lamp in the socket, usually in avertical position with the base up. This creates a situation not found in the application and use of ordinary lamps having a screw base as a socket must be provided that will provide a perfect mechanical and electrical contact between the lamp prongs and current carrying parts of the socket; which will have adequate current carrying capacity; which will support the lamp without subjecting it to mechanical strains; which will automatically compensate for any variation in the size and spacing oi. the prongs resulting from uncontrollable manufacturing errors, and which will securely hold the lamp from falling and still permit its ready insertion and removal from the socket.

Heretofore, it has been the practice to use a socket having contact elements in the form of spring clips which grip the lamp prongs when the lamp is inserted into the socket and rotated. Separate spring members are provided for engaging an annular slot in the prong to hold the lamp in the socket.

Sockets of this type have not proven successful as they do not provide adequate electrical contact between the lamp prongs and contact elements, do not readily compensate for variations in size and spacing of the prongs thereby subjecting the lamp to unnecessary and detrimental strains, and do not provide for obtaining sufllcient wiping action between the lamp prongs and contact'elements of the socket during insertion and removal of the lamp.

The object of my invention is to provide a socket for bi-post lamps which'shall be of simple construction, economical to make and which is specially designed to provide a substantially periect electrical contact between the lamp prongs and contact elements of the socket without subjecting the lamp to unnecessary and detrimental strains.

A more specific object of my invention is to provide a socket for bi-post lamps having floating contact elements which compensate for any variation in size and spacing of the lamp prongs without reducing the current carrying capacity 5 01 the socket and which ensure a wiping action between the prongs and contact elements during insertion and removal of the lamp.

Another object of my invention is to provide a socket for bi-post lamps wherein the contact ele 1o ments thereof function both, to conduct current to the lamp and mechanically lock the lamp in the socket while permitting ready insertion and removal of the lamp.

A further object of the invention is to provide 15 a socket for bi-post lamps which shall support. the lamp by its prongs with the lamp base out of engagement with the body of the socket thereby eliminating all strains on the lamp.

These and other objects of the invention will. 1) become more apparent from thefollowing detailed description of a preferred embodiment taken in conjunction with the drawing wherein;

Figure -1 is a partially sectionalized view in elevation along line 1-1 of Fig. 2 of a lamp socket is embodying the principal features of the invention and also showing the manner in which the lamp is supported,

Fig. 2 is a bottom plan view of the socket of Fig. 1 showing the position of the contactor eleso ments therein,

Figs. 3 and 4 are enlarged views of the contaigor elements showing details of construction, an

Fig. 5 is a view showing how a cut-out device 35 may be applied to the socket to adapt it for series-circuit operation.

Briefly, in the practice of my invention, I provide a socket having a body of porcelain, or other suitable composition, with contactor elements 0 mounted therein which are in the form of split socket elements so constituted and positioned that the lamp is supported entirely from its prongs and that they compensate for any variation in the size and .spacing of the lamp prongs. 5

' The two sections of each. contact element are and lamp II. The socket comprises generally a body '2 of porcelain or other suitable composition, and a pair of contactors II, the construction of which is shown more clearly in Figs. 3 and 4.

The body I2 is provided with bottom recesses M to receive the contactors i3, which are secured therein as shown in Fig. l, and with top recesses 95 for the line terminals of the contactors.

The lamp for which the socket I is especially adapted is known as a bi-post lamp and comprises a glass envelope it which encloses the fllamentand a pair of metal prongs i! which are moulded into the glass base of the envelope.

In order to securely support the lamp and conduct current to the filament thereof without subw jecting the prongs and envelope toundue strain.

and to provide good electrical contact, the contactors i3 are so constructed as to readily adjust themselves to the size and spacing of the prongs and at the same time provide a large and eflective contact area. I I

With reference to Figs. 3 and 4, it will be observed that each contactor l3 comprises generally a split socket'portion l3 and a stem portion i9 integral .with one part thereof which is threaded as shown to receive a locking nut which holds' thecontaotor inthe body member of' the socket. In this instance the lower'part of the socketfportion I3 is tubular in shape while the upper part thereof adjacent the stem is square.

The socket portion I3 is constructed in two parts one of which may be termed the rigid member 22 which is integral with the stem and the other the movable or floating part 23 which is loosely and resiliently supported from the rigid.

part. In other words, the socket portion of the contactor is of split construction as best shown in Fi 4. L

In order to electrically connect the floating part 23 to the rigid or stationary part 22 and thereby increase the current carrying capacity of;

the socket, a'split copper shunt2l may be provided which encircles these parts and makes them as one electrically while'at the same time permit ting relative transverse movement therebetween.

The two parts of the socket portion may be biased together in any suitable manner such as by means of a split band spring 25 disposed thereabout and over the copper shunt 24. As will be .readily understood, this permits the two parts of the socket portion to be forced apart by the lamp prong when the lamp is inserted.

With a view to providing for securely locking 'the lamp within the socket but at the same time permitting of its ready removal and insertion, the socket contactors are each provided with look-- ing means in the form of a spring pressed ball bearing 26 mounted within a suitable cavity adjacent the open end of the rigid part of the socket as shown best in Fig. 4. A suitable leaf spring member 21 mounted on the side of the rigid part serves to bias the ball 26 inwardly so that it projects slightly into the bore of the socket portion where it engages the annular slot 28 in the lamp floating part to move away from and toward the rigid or stationary part in a deflnite path and also eliminates any tendency of this part to drop downwardly or become misplaced in any way.

In order that the contactors l3 will receive the lamp prongs with the least possible resistance, the end openings therein are chamfered as shown at 33. This chamfer is also shaped to conform generally to the shape of the base of the lamp prong which engages therewith as shown in Fig. ,1.

It will be observed that the lower end of the socket body i2 is so shaped that there is no mechanical engagement between it and the base of the lamp thus relieving all strain from the lamp which is entirely supported by its prongs i1. '13

With reference to Fig. 2, it will be seen that the contactors l3 are positioned within their respective recesses I in the body i2 in such manner that the floating parts 23 are to the outside and move in spaced parallel planes, and not in so the same plane. This arrangement provides the best operating position as it permits the socket portions to readily adjust themselves to slight variations in the spacing of the lamp prongs while at the same time producing the best possible con- :5 tact engagement between the prongs I sockets.

In view of the foregoing detailed description of the preferred form of the invention, it will be apparent-that a lamp socket .especiallyadopted for bi-post lamps has been provided which will 30 not onlysecurely support the lamp without subjecting it to strains but which ensures substantially perfect mechanical and electrical contact between the lamp prongs and the current carrying parts of the socket; provides a large contact 85 area thereby eliminating excessive heating and pitting which automatically adjusts itseli'v .to

variations in the spacing of the lamp prongs and which ensures a wiping action between the socket portions and the lamp prongs to remove any ac- 4o cumulation of dirt or corrosion or both. .In addif .ticn, the socket is of simple and extremely rugged I with prongs 34 anda cut-out device 35 as shown in Fig. 5. The prongs 3lmay be attacheddirectly to the stem portions IQ of the socket contactors i3.

Itmay be stated, in conclusion, that, 'while'the illustrated example constitutes a practical embodiment of my invention, I do not wish to limit myself strictly to the exact details herein illustrated, since modifications of the same maybe made without departing from the spirit of the invention, as defined in the appended claims.

I claim as my invention:

l. A socket for bi-post lamps having a-plurality of terminal prongs extending through the' base thereof comprising a body member of insu- 05 lating material, and a plurality of contactor elements disposed therein, each of said contactor elements comprising separate cooperating sta tionary and movable parts biased together with a band spring encircling said parts to provide a 7 socket to receive the terminal prong of the lamp and a shunt positioned beneath the band spring and also encircling said parts for electrically connecting the said stationary and movable parts together, said contactor elements functioning to support the lamp with its base out of engagement with the body member of the socket.

2. A socket for bi-post lamps having a pair of terminal prongs extending through the base thereof comprising, a body member, and a pair of metallic contactor elements mounted thereon adapted to engage the lamp prongs, said contactor elements each comprising an elongated socket portion of tubular construction split longitudinally and transversely to provide separate stationary and movable cooperating parts, the stationary part of each .being attached directly to the body member and the separate movable part being resiliently attached to its associated stationary part by means of a band spring encircling said parts, thereby to permit relative lateral expansion and contraction of the two parts, ,a flexible shunt member connecting the stationary and movable parts of the socket portion together electrically, and means attached to said stationary part and engaging the said movable part for guiding the lateral movements of said movable part, said contactor elements functioning to support the lamp with its base out of engagement with the body member.

3. A contactor element adapted to receive an elongated terminal member comprising, a metallic body member having a socket portion with an annular groove in the outside surface thereof, said socket portion being divided longitudinally and cut transversely to provide two separate and relatively movable cooperating parts one of which is integral with the body member and the other of which is separate and movable laterally of the first part, a band spring disposed in said annular groove and encircling said parts of the socket portion to resiliently bias said parts together, a pin member mounted on the first part of the socket portion which is integral with the body member and extending transversely through an opening in the movable part of the socket portion to loosely maintain said movable part in position and guide its lateral movements, a flexible shunt member connecting the two separate parts of the socket portion together electrically, and resilient means mounted at the 'open end of the socket portion disposed to mechanically engage said elongated terminal member when said member is inserted into the socket portion of the contactor element.

4. A contactor element for lamp sockets and the like adapted to receive an elongated terminal member comprising, a socket portion havin separate cooperating parts disposed for separate lateral movement, a stem member attached to one of said parts, a band spring member encircling said separate parts of the socket portion intermediate the ends thereof to resiliently bias said parts together, a band shunt member also .0 encircling said parts and disposed beneath the band spring member to be retained in position thereby to electrically connect said parts together, and resilient means mounted adjacent the open end of said socket portion for mechanically engaging said elongated terminal member when said terminal member is inserted into the socket portion of the contactor element.

5. A contactor element for lamp sockets and the like adapted to receive an elongated terminal member on a lamp comprising, a stem member for mounting the contactor element, a socket portion having separate cooperating parts dis- .posed for relative lateral movement, one of said parts being attached to the stem member, the other of said parts being mounted on the first part, a spring member encircling said parts intermediate the ends thereof to resiliently hold them together in expansible relation, a flexible shunt member disposed beneath the spring member and retained thereby in direct engagement with both of said parts for electrically connecting them together, means attached to the part of the socket portion which is attached to the stem member for retaining the other separate part of the socket portion in position and guiding its lateral -movements, and locking means mounted adjacent the open end of the socket portion disposed to mechanically engage said elongated terminal member when said terminal member is inserted into the socket portion of the contactor element.

6. A contactor element adapted to receive an elongated terminal member comprising, a metallic body member having an elongated tubularshaped socket portion with a longitudinal bore therein to receive the elongated terminal member, said socket portion being split longitudinally and cut transversely to form physically separate cooperating parts, said parts having a shallow annular groove in the outside surfaces intermediate the ends thereof, a mounting stud attached to one of said parts, a band spring disposed in said annular groove and encircling said separate parts of the socket portion to resiliently bias said parts together and permit relative transverse movement therebetween, said separate parts of the socket portion having a transverse opening therethrough adjacent the bottom thereof, the opening in one of said parts being threaded, a retaining member disposed in said transverse opening in threaded engagement with the said threaded opening, a flexible shunt member connecting said separate parts of the socket portion together electrically, and a resilient locking member mounted on the socket portion adjacent the open end thereof disposed to mechanically engage the said elongated terminal member when inserted into the socket portion.

SAMUEL B. KRAUT. 

